From 0f864310322e346a522c0c2fe7578e8d5a1f73fd Mon Sep 17 00:00:00 2001
From: Chris Tomlinson <chris@c3st7n.com>
Date: Sat, 16 Nov 2019 22:32:09 +0000
Subject: [PATCH 1/2] Add From trait for NonZero ints to NonZero ints

---
 src/libcore/num/mod.rs | 57 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index b5d61a3fd4e7..9e336f02869b 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -134,6 +134,63 @@ macro_rules! from_str_radix_nzint_impl {
 from_str_radix_nzint_impl! { NonZeroU8 NonZeroU16 NonZeroU32 NonZeroU64 NonZeroU128 NonZeroUsize
                              NonZeroI8 NonZeroI16 NonZeroI32 NonZeroI64 NonZeroI128 NonZeroIsize }
 
+// Conversion traits for NonZero integer types to wider NonZero types
+macro_rules! impl_nz_from_nz {
+    ($Small: ty, $Large: ty, $LargePrimitive: ty, #[$attr:meta], $doc: expr) => {
+        #[$attr]
+        #[doc = $doc]
+        impl From<$Small> for $Large {
+            #[inline]
+            fn from(small: $Small) -> $Large {
+                // we already know a NonZero will not contain a zero
+                unsafe {
+                    <$Large>::new_unchecked(small.get() as $LargePrimitive)
+                }
+            }
+        }
+    };
+    ($Small: ty, $Large: ty, $LargePrimitive: ty, #[$attr:meta]) => {
+        impl_nz_from_nz!($Small,
+                   $Large,
+                   $LargePrimitive,
+                   #[$attr],
+                   concat!("Converts `",
+                           stringify!($Small),
+                           "` to `",
+                           stringify!($Large),
+                           "` losslessly.
+
+```rust
+let small = core::num::", stringify!($Small), "::new(5).unwrap();
+let big: core::num::", stringify!($Large), " = small.into();
+"));
+    }
+}
+
+// NonZeroUnsigned -> NonZeroUnsigned wider
+impl_nz_from_nz! { NonZeroU8, NonZeroU16, u16, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU8, NonZeroU32, u32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU8, NonZeroU64, u64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU8, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU16, NonZeroU32, u32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU16, NonZeroU64, u64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU16, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU32, NonZeroU64, u64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU32, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU64, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+
+// NonZeroSigned -> NonZeroSigned wider
+impl_nz_from_nz! { NonZeroI8, NonZeroI16, i16, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI8, NonZeroI32, i32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI8, NonZeroI64, i64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI8, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI16, NonZeroI32, i32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI16, NonZeroI64, i64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI16, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI32, NonZeroI64, i64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI32, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI64, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+
 /// Provides intentionally-wrapped arithmetic on `T`.
 ///
 /// Operations like `+` on `u32` values is intended to never overflow,

From 5cc730c85d8f72fdc391e691b1b1cabf3fef8410 Mon Sep 17 00:00:00 2001
From: Chris Tomlinson <chris@c3st7n.net>
Date: Sat, 16 Nov 2019 23:38:12 +0000
Subject: [PATCH 2/2] Fix tidy errors

---
 src/libcore/num/mod.rs | 62 ++++++++++++++++++++++++++++--------------
 1 file changed, 41 insertions(+), 21 deletions(-)

diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 9e336f02869b..f0a8b801ccd2 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -142,7 +142,7 @@ macro_rules! impl_nz_from_nz {
         impl From<$Small> for $Large {
             #[inline]
             fn from(small: $Small) -> $Large {
-                // we already know a NonZero will not contain a zero
+                // SAFETY: we already know a NonZero will not contain a zero
                 unsafe {
                     <$Large>::new_unchecked(small.get() as $LargePrimitive)
                 }
@@ -168,28 +168,48 @@ let big: core::num::", stringify!($Large), " = small.into();
 }
 
 // NonZeroUnsigned -> NonZeroUnsigned wider
-impl_nz_from_nz! { NonZeroU8, NonZeroU16, u16, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU8, NonZeroU32, u32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU8, NonZeroU64, u64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU8, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU16, NonZeroU32, u32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU16, NonZeroU64, u64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU16, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU32, NonZeroU64, u64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU32, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroU64, NonZeroU128, u128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU8, NonZeroU16, u16,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU8, NonZeroU32, u32,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU8, NonZeroU64, u64,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU8, NonZeroU128, u128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU16, NonZeroU32, u32,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU16, NonZeroU64, u64,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU16, NonZeroU128, u128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU32, NonZeroU64, u64,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU32, NonZeroU128, u128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroU64, NonZeroU128, u128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
 
 // NonZeroSigned -> NonZeroSigned wider
-impl_nz_from_nz! { NonZeroI8, NonZeroI16, i16, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI8, NonZeroI32, i32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI8, NonZeroI64, i64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI8, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI16, NonZeroI32, i32, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI16, NonZeroI64, i64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI16, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI32, NonZeroI64, i64, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI32, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
-impl_nz_from_nz! { NonZeroI64, NonZeroI128, i128, #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI8, NonZeroI16, i16,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI8, NonZeroI32, i32,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI8, NonZeroI64, i64,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI8, NonZeroI128, i128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI16, NonZeroI32, i32,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI16, NonZeroI64, i64,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI16, NonZeroI128, i128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI32, NonZeroI64, i64,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI32, NonZeroI128, i128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
+impl_nz_from_nz! { NonZeroI64, NonZeroI128, i128,
+    #[unstable(feature = "nonzero_int_to_wider_nonzero_int_lossless_conv", issue = "66196")] }
 
 /// Provides intentionally-wrapped arithmetic on `T`.
 ///